Nonlinear properties and stability against DC accelerated aging stress of praseodymium oxide-based ZnO varistors by Er2O3 doping

The microstructure, nonlinear properties, and stability against DC accelerated aging stress of ZnO–Pr6O11–CoO-based varistors doped with Er2O3 was investigated at sintering temperatures of 1300 and 1350 °C. The addition of Er2O3 to ZnO–Pr6O11–CoO-based varistor greatly improved the nonlinear properties and the varistor sintered at 1300 °C exhibited good nonlinearity, with nonlinear exponent of 52.8 and leakage current of 9.8 μA The increase of sintering temperature deteriorated the nonlinear properties, whereas it greatly improved the stability.